Combustion control using ion sense feedback and multi-strike spark to manage high dilution and lean AFR

Abstract

A system and method for operating a multiple cylinder internal combustion engine having at least one actuator for controlling charge dilution of at least one cylinder and at least one spark plug per cylinder include attempting to improve combustion quality by modifying ignition energy of the at least one spark plug before modifying charge dilution of the cylinder, and modifying both ignition energy and charge dilution substantially simultaneously to establish combustion if an ionization sense signal associated with the cylinder indicates a misfire.

1. A multiple cylinder internal combustion engine having at least one spark plug associated with each cylinder and at least one actuator for controlling charge dilution of at least one cylinder, the engine comprising:
 a controller in communication with the at least one actuator and the at least one spark plug, the controller attempting to improve combustion quality as determined by an ionization sensing signal associated with a selected cylinder by modifying ignition energy of the at least one spark plug before modifying charge dilution of the cylinder. 
 
     
     
       2. The engine of  claim 1  wherein the controller adjusts both ignition energy and charge dilution substantially simultaneously to establish combustion if an ionization sensing signal associated with the cylinder indicates a misfire. 
     
     
       3. The engine of  claim 2  wherein the controller reduces charge dilution and increases ignition energy to initiate combustion in response to detecting the misfire. 
     
     
       4. The engine of  claim 3  wherein the engine includes an exhaust gas recirculation valve and wherein the controller actuates the exhaust gas recirculation valve to reduce charge dilution. 
     
     
       5. The engine of  claim 4  wherein the engine increases a number of sparks per combustion cycle to increase ignition energy. 
     
     
       6. The engine of  claim 3  wherein the controller actuates at least one of a throttle valve and fuel injector to enrich an air/fuel ratio to reduce charge dilution. 
     
     
       7. The engine of  claim 1  wherein the at least one actuator comprises an exhaust gas recirculation valve and wherein the controller actuates the exhaust gas recirculation valve to modify charge dilution of the cylinder. 
     
     
       8. The engine of  claim 1  wherein the at least one actuator comprises at least one gas exchange valve and wherein the controller adjusts timing of the at least one valve to modify charge dilution of the cylinder. 
     
     
       9. The engine of  claim 1  wherein the controller increases a number of sparks per combustion cycle for the at least one spark plug to modify ignition energy. 
     
     
       10. A computer readable storage medium having code representing instructions executable by a microprocessor based controller to control combustion within a multiple cylinder internal combustion engine having at least one spark plug per cylinder and at least one actuator for controller charge dilution of at least one cylinder, the computer readable storage medium comprising:
 code that attempts to improve combustion quality as determined by an ionization sensing signal associated with a selected cylinder by modifying ignition energy of the at least one spark plug before modifying charge dilution of the cylinder; and 
 code that adjusts both ignition energy and charge dilution substantially simultaneously to establish combustion if an ionization sensing signal associated with the cylinder indicates a misfire. 
 
     
     
       11. The computer readable storage medium of  claim 10  further comprising code that reduces charge dilution and increases ignition energy to initiate combustion after detecting the misfire. 
     
     
       12. The computer readable storage medium of  claim 10  further comprising code that actuates an exhaust gas recirculation valve to reduce charge dilution by reducing the amount of recirculated exhaust gas. 
     
     
       13. The computer readable storage medium of  claim 10  further comprising code that increases a number of sparks per combustion cycle for the at least one spark plug to increase ignition energy of the at least one cylinder. 
     
     
       14. The computer readable storage medium of  claim 10  wherein the code comprises code that controls a charge motion control device such that combustion burn rate determined by ionization sensing feedback approaches a desired combustion burn rate selected in response to current engine operating conditions. 
     
     
       15. A method for controlling a multiple cylinder internal combustion engine, the method comprising:
 controlling charge dilution and ignition energy to achieve desired combustion quality by first adjusting ignition energy and adjusting charge dilution only if ignition energy adjustments do not result in the desired combustion quality. 
 
     
     
       16. The method of  claim 15  further comprising monitoring an ionization sensing signal associated with a selected cylinder to provide an indication of combustion quality. 
     
     
       17. The method of  claim 15  further comprising:
 increasing a number of sparks per combustion cycle to adjust ignition energy to achieve the desired combustion quality. 
 
     
     
       18. The method of  claim 15  further comprising:
 reducing recirculated exhaust gas to control charge dilution and achieve the desired combustion quality. 
 
     
     
       19. The method of  claim 15  further comprising:
 reducing charge dilution and increasing ignition energy substantially simultaneously if an ionization sensing signal associated with a selected cylinder indicates a misfire. 
 
     
     
       20. The method of  claim 15  wherein adjusting ignition energy includes adjusting the number of sparks per combustion cycle and wherein adjusting charge dilution includes adjusting the amount of recirculated exhaust gas supplied to a selected cylinder.